Various classes of graphical models describe computations that can be performed on application specific computational hardware, such as a computer, microcontroller, FPGA, and custom hardware. Classes of such graphical models can include, but are not limited to time-based block diagrams, such as those found within Simulink® software from The MathWorks, Inc. of Natick, Mass.; state-based and flow diagrams, such as those found within Stateflow® software from The MathWorks, Inc. of Natick, Mass.; and data-flow diagrams, such as those found in LabVIEW® from National Instruments Corporation of Austin, Tex. A common characteristic among these various forms of graphical models is that they define semantics on how to execute the diagram.
Historically, engineers and scientists have utilized time-based graphical models in numerous scientific areas such as feedback control theory and signal processing to study, design, debug, and refine models of a system, such as a dynamic system. Dynamic systems, which can be characterized by the fact that their behaviors change based on, for example, input stimuli, time, conditions or events, are representative of many real-world systems. Time-based graphical modeling has become particularly attractive over the last few years with the advent of software packages such as Simulink® software. Such packages provide sophisticated software platforms with a rich suite of support tools that makes the modeling, analysis and design of dynamic systems efficient, methodical, and cost-effective.
A dynamic system (either natural or man-made) is a system whose response at any given time is a function of its input stimuli, its current state, and the current time. Such systems may range from simple to highly complex systems. Physical dynamic systems may include such things as falling bodies, the rotation of the earth, bio-mechanical systems (muscles, joints, etc.), bio-chemical systems (gene expression, protein pathways), weather/climate pattern systems, etc. Examples of man-made or engineered dynamic systems can include: a bouncing ball, a spring with a mass supported on an end, automobiles, airplanes, control systems in appliances, communication networks, audio signal processing, power plant control systems, stock trading systems, etc.
Professionals from diverse areas such as engineering, science, education, and economics build mathematical models of dynamic systems in order to better understand system behavior as it changes with the progression of time. These models may also be used in education, such as for teaching basic principles governing physical systems. Graphical models may be used in the specification, development, analysis, verification and validation, testing, and calibration of dynamic systems.
For many systems, the knowledge of end-to-end delay can be important in designing models of systems in graphical modeling environments. Model designers may not be able to access and/or analyze delays associated with existing models.